Desquamative enteropathy and pyloric atresia without skin disease caused by a novel intracellular beta4 integrin mutation.
BACKGROUND
Mutations in alpha6 or beta4 integrins (ITGA6, ITGB4) are known to cause junctional epidermolysis bullosa with pyloric atresia (JEB-PA), often lethal in infancy through skin desquamation. There is 1 report of pyloric atresia associated with a desquamatory enteropathy but without skin disease, of unknown molecular basis.


METHODS
We report 2 Kuwaiti siblings with pyloric atresia and life-threatening intestinal desquamation without significant skin abnormality. The older sibling died of intractable diarrhoea, and the younger sibling suffered episodes of massive protein-losing enteropathy, triggered by viral infections, in addition to obstructive uropathy. Mutation analysis was performed for ITGA6 and ITGB4 and expression of ITGA6 and ITGB4 protein was examined in skin and intestinal biopsies. Her serum also was incubated with normal intestine.


RESULTS
We identified a novel mutation in ITGB4, with homozygous deletion of a single residue (isoleucine 1314) within the intracellular plectin-binding domain. Expression of ITGA6 and ITGB4 within skin, duodenal, and colonic epithelium was normal or minimally reduced, in contrast to previous reports. Biopsies taken during relapse showed accumulation of immunoglobulin G and C1q within intestinal basement membrane, whereas immunoglobulin G from her serum bound to basement membrane of normal small intestine. Immunomodulatory therapy induced significant improvement following relapses.


CONCLUSIONS
ITGB4 mutation may induce a desquamative enteropathy in infancy without significant skin disease. A history of pyloric atresia is important in infants with severe chronic diarrhoeal disease and should prompt investigation for JEB-PA associated mutations. Acquired immune responses may exacerbate primary genetic disorders of epithelial adhesion and immunomodulatory therapy may be beneficial.
Salvestrini
Camilla
C
Centre for Paediatric Gastroenterology, Royal Free Hospital, London, UK.
McGrath
John A
JA
Ozoemena
Linda
L
Husain
Khaled
K
Buhamrah
Eman
E
Sabery
Nasim
N
Leichtner
Alan
A
Rufo
Paul A
PA
Perez-Atayde
Antonio
A
Orteu
Cate H
CH
Torrente
Franco
F
Heuschkel
Robert B
RB
Thomson
Michael A
MA
Murch
Simon H
SH
D003967:Diarrhea / Q000235:genetics / Q000473:pathology / Q000628:therapy; D004065:Digestive System Abnormalities / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D004751:Enteritis / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D016109:Epidermolysis Bullosa, Junctional / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D005260:Female; D006801:Humans; D007223:Infant; D039663:Integrin beta4 / Q000235:genetics*; D007413:Intestinal Mucosa / Q000473:pathology; D007422:Intestines / Q000473:pathology / Q000503:physiopathology; D009154:Mutation; D010288:Parenteral Nutrition; D011708:Pylorus / Q000002:abnormalities / Q000473:pathology* / Q000503:physiopathology; D012867:Skin / Q000473:pathology / Q000503:physiopathology
D039663:Integrin beta4